Dental cartridge

ABSTRACT

A dental cartridge ( 10 ) for dispensing a dental cartridge substance ( 26 ). The dental cartridge ( 10 ) has a dispensing region ( 18 ) which is of substantially constant internal diameter. The dispensing region ( 18 ) is at least partially curved. A deformable piston ( 24 ) is provided and arranged to pass through the curved portion of the dispensing region ( 18 ).

FIELD OF THE INVENTION

The present invention relates to a dental cartridge.

It is known to require a container in which a dental substance (forinstance a cavity filling material) may be stored without contact tolight, and from which the substance may be directly dispensed to arequired location on or inside a patient's tooth. Various devices havebeen used for this purposes, including cylindrical tubes with hollow,angular protrusions, torroidal cartridges with co-axial nozzles, andcylindrical cartridges with curved, tapered dispensing nozzles.

Several problems are commonly experienced with such dental containers.Many dental substances are complex mixtures of materials, withparticular properties. The effect of shear forces inherent in many ofthe above designs can be to undesirably change the properties of thefilling material. Other materials may not be extrudable through reduceddiameter nozzles. A further problem is that dental substances are oftenwasted due to the impossibility of completely emptying such containersby the application of a conventional plunging mechanism.

The present invention attempts to overcome at least in part some of theaforementioned disadvantages of previous dental substance dispensers.

SUMMARY OF THE PRESENT INVENTION

In accordance with one aspect of the present invention there is provideda dental cartridge for dispensing a dental substance, characterized inthat the dental cartridge is hollow and has a dispensing region ofsubstantially constant internal dimension, said dispensing region beingcurved at least in part, and a piston having a first end, the first endof the piston having an external dimension conforming with the internaldimension of the dispensing region, the piston being arranged so as tobe able to pass through the dispensing region including the curved partthereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described, by way of example, withreference to the accompanying drawings, in which:

FIG. 1 is a cross sectional view of a dental cartridge in accordancewith the present invention;

FIG. 2 is a cross sectional view of the dental cartridge of FIG. 1 whichhas been prepared for use;

FIG. 3 is a cross sectional view of the dental cartridge of FIG. 1 afteruse;

FIG. 4 is a cross sectional view of a second embodiment of the dentalcartridge of the present invention which has been prepared for use;

FIG. 5 is a cross sectional view of a third embodiment of the dentalcartridge of the present invention which has been prepared for use.

FIG. 6 is a cross sectional view of a fourth embodiment of the dentalcartridge of the present invention which has been prepared for use.

DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 to 3 of the accompanying drawings, there is shown adental cartridge 10 having a first end 12 and a second end 14. Thecartridge 10 includes an introducing region 16 of circular cross sectionand substantially constant internal radius adjacent the first end 12,and a dispensing region 18, also of circular cross section andsubstantially constant internal radius, adjacent the second end 14. Asshown, the internal radius of the dispensing region 18 may be smallerthan that of the introducing region 16.

Typically, the cartridge 10 is formed of an opaque plastic material.Further, the internal diameter of the dispensing region 18 is preferablyin the range from 1 mm to 6 mm.

The introducing region 16 is straight and extends from the first end 12of the dental cartridge 10 to an intermediate interface 17. Theintroducing region 16 is generally cylindrical in shape with alongitudinal axis 20. An outwardly extending flanged portion 22 islocated adjacent the first end 12 of the introducing region 16. Theflanged portion 22 is circular and has an external radius greater thanthat of the remainder of the introducing region 16. The flanged portion22 allows the dental cartridge 10 to be attached, in use, to adispensing device (not shown).

The introducing region 16 is in communication with the exterior of thedental cartridge at the first end 12, and is in communication with thedispensing region 18 at the intermediate interface 17.

The dispensing region 18 extends from the intermediate interface 17 tothe second end 14 of the dental cartridge 10. The dispensing region 18is curved in such a way that at the intermediate interface 17 thelongitudinal axis of the dispensing region 18 is co-axial with thelongitudinal axis 20 of the introducing region 16, whereas at the secondend 14 the longitudinal axis of the dispensing region 18 is orientatedat an angle with respect to axis 20.

The internal radius of the dispensing region 18 is substantiallyconstant to provide, in use, a fluid flow path substantially free ofshearing forces. The external radius of the dispensing region 18 maytaper from a radius equal to the external radius of the introducingregion 16 at the intermediate interface 17 to a smaller radius at thesecond end 14. In this case, the wall thickness of the introducingregion 16 is thus smaller at the second end 14 than at the interface 17.

FIG. 2 shows the present invention in a state immediately prior to use.At least a portion of the dispensing region 18 adjacent the second end14 contains a quantity of a dental substance 26. A deformable piston 24is introduced into the dental cartridge 10 through the introducingregion 16. The deformable piston 24 is generally cylindrical in shape,with an external radius approximately equal to the internal radius ofthe dispensing region 18. The deformable piston 24 has a first end 28which abuts the dental substance 26 and a second or free end 30initially located outside of the dental cartridge 10. It will beappreciated that the deformable piston 24 may be of anotherconfiguration, provided the first end 28 is substantially complementaryin shape to the interior of the dispensing region 18.

In use, at least a portion of the dispensing region 18 is loaded with aquantity of a dental substance 26, and a deformable piston 24 isintroduced through the introducing region 16. Application of a pushingforce on the free end 30 of the deformable piston 24 causes thedeformable piston 24 to move through the dental cartridge 10, thusdispensing the dental substance 26 from the second end 14 of thedispensing region 18 on or into the desired location. The deformable orflexible nature of the piston 24 enables the piston 24 to travel throughthe curved portion of the dispensing region 18 whilst conforming closelywith the internal walls of the dispensing region 18.

FIG. 3 shows the dental cartridge 10 of FIG. 2 after use, where thedeformable piston 24 has completely displaced the dental substance 26 inthe dispensing region 18.

A second embodiment of the present invention is shown in FIG. 4, wherethe introducing region 16 and the dispensing region 18 have the sameinternal radius. In this embodiment the intermediate interface 17 is notdistinguishable from the introducing region 16 and the dispensing region18.

A third embodiment of the present invention is shown in FIG. 5. In thisembodiment the dispensing region 18 includes a straight portion 19adjacent the intermediate interface 17, in which the straight portion 19has a longitudinal axis which is co-axial with the longitudinal axis 20of the introducing region 16.

A fourth embodiment is shown in FIG. 6. This embodiment also includes astraight portion 19 which has an, internal radius equal to that of boththe introducing region 16 and the dispensing region 18.

It is envisaged that the piston 24 could be made in various lengths andshapes so that in some embodiments the piston 24 could be relativelyshort whilst in other embodiments the piston 24 could be relativelylong.

Further, it is envisaged that when the cartridge 10 contains a dentalsubstance 26 the second end 14 could be closed off by an opaque cap toprevent ingress of radiation.

Modifications and variations as would be apparent to a skilled addresseeare deemed to be within the scope of the present invention. Forinstance, the flanged portion 22 may be replaced with another means forattaching the dental cartridge 10 to a dispensing device, such as a Luerlock flange, a flange with a threaded portion, or a circumscribinggroove on the external surface of the introducing region 16.

1. A dental cartridge for dispensing a dental substance, wherein the dental cartridge is hollow and has a dispensing region of substantially constant internal dimension, said dispensing region having a curved part, the dispensing region containing a quantity of a dental substance within the curved part, the dental cartridge including a piston comprised of a unitary deformable member, the piston having a first end, the first end of the piston having an external dimension conforming with the internal dimension of the dispensing region, the piston being arranged so as to be able to pass through the dispensing region including the curved part thereof for displacing and dispensing the dental substance from the dispensing region including the curved part thereof substantially free of shearing forces.
 2. A dental cartridge according to claim 1, wherein the piston is in the form of a cylinder.
 3. A dental cartridge according to claim 1, wherein the dental cartridge has a first end and second end, the first end being remote from the dispensing region and the second end being adjacent an outer end of the dispensing region, and wherein the dental cartridge has an introducing region of substantially constant internal dimension extending from the first end, the piston being receivable within the introducing region.
 4. A dental cartridge according to claim 3, wherein the internal dimension of the introducing region is larger than the internal dimension of the dispensing region.
 5. A dental cartridge according to claim 3, wherein the introducing portion is substantially circular in cross section.
 6. A dental cartridge according to claim 3, wherein the dental cartridge includes a portion adjacent the first end for attachment to a dispensing device.
 7. A dental cartridge according to claim 6, wherein the portion for attachment to a dispensing device is in the form of an outwardly extending flange.
 8. A dental cartridge according to claim 6, wherein the portion for attachment to a dispensing device is at least partially threaded.
 9. A dental cartridge according to claim 6, wherein the portion for attachment to a dispensing device includes a Luer lock.
 10. A dental cartridge according to claim 6, wherein the portion for attachment to a dispensing device includes a circumscribing groove.
 11. A dental cartridge according to claim 1, wherein the dispensing region has an external dimension which tapers in size and is smallest at a second end of the dental cartridge.
 12. A dental cartridge according to claim 1, wherein the dispensing region includes a substantially straight portion.
 13. A dental cartridge according to claim 1, wherein the dispensing region is substantially circular in cross section.
 14. A dental cartridge according to claim 13, wherein the dispensing region has an internal diameter in the range 1 mm to 6 mm. 